表面粗さを考慮した燃焼炎3 段階合成法によるダイヤモンド皮膜合成

抄録

  A flame combustion method enables the synthesis of diamond using acetylene-oxygen gas in ambient atmosphere. It has various advantages over other methods. We previously synthesized diamond films on a Mo substrate surface by the flame combustion method. In this method, most diamond films delaminate as a result of thermal stress during cooling. To prevent diamond film delamination for the synthesis of good diamond films, a three-step synthesis method was proposed. However, the surface roughness of synthesized diamond films by this method became large. In this study, to reduce the surface roughness of synthesized diamond films by flame combustion and to achieve good adhesion on the Mo substrate, the flow ratio of oxygen flow rate to acetylene flow rate and synthesis time of the three-step synthesis method were varied during the synthesis of diamond. We previously determined optimal ratio of oxygen flow rate (F_o = 63.8 cm³/s) to acetylene flow rate (F_a = 70.9 cm³/s) which was set to R_f = F_o/F_a = 0.90, because delamination free good crystalline growth could be obtained at R_f = 0.90. The acetylene flow rate was carefully varied in the range of 63.8-75.1 cm³/s (R_f = 0.85-1.00) of each synthesis time (10 min) of the three-step synthesis method. The oxygen flow rate was not varied, and it was 63.8 cm³/s. To investigate the surface morphology and the surface roughness of synthesized diamond films, synthesized films were observed. The flow ratio and synthesis time of the three-step synthesis method affected the surface morphology and the surface roughness of synthesized diamond films. The surface roughness of the synthesized film was reduced by the proposed method in this study. The surface roughness in the Case 3 condition was the smallest in this experiment.